Radioimmunoassay of human arginine-rich apolipoprotein, apoprotein E. Concentration in blood plasma and lipoproteins as affected by apoprotein E-3 deficiency

J Clin Invest. 1980 Dec;66(6):1351-62. doi: 10.1172/JCI109988.


A radioimmunoassay for apolipoprotein E in human blood serum has been developed that measures equally the major polymorphic species of the protein (apolipoproteins E-1, E-2, E-3, and E-4) and the apo E in the dimer of apolipoproteins E and A-II. The assay is specific and yields values for apolipoprotein E in very low density lipoproteins that agree closely with those obtained by a quantitative electrophoretic method. Apolipoprotein E is also present in at least one species of high density lipoprotein, but the content of apolipoprotein E in the lipoprotein fractions of plasma is uncertain owing to dissociation during ultracentrifugation. The concentration of apolipoprotein E is higher in serum of normolipidemic, premenopausal women than in men of comparable age and is a direct function of the serum triglyceride level. Apolipoprotein E levels are increased out of proportion to triglyceride levels in hyperlipidemic patients with familial dysbetalipoproteinemia (homozygotes for lack of apolipoprotein E-3). Heterozygous relatives of homozygotes have significantly higher apolipoprotein E levels in serum than unaffected relatives. The concentration of partially degraded (remnant) triglyceride-rich lipoproteins also appears to be increased in heterozygotes, who comprise about 15% of the population.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / analysis
  • Antibody Specificity
  • Apolipoproteins / analysis*
  • Apolipoproteins / blood
  • Apolipoproteins / deficiency
  • Heterozygote
  • Homozygote
  • Humans
  • Hypobetalipoproteinemias / blood*
  • Hypobetalipoproteinemias / genetics
  • Hypolipoproteinemias / blood*
  • Radioimmunoassay
  • Triglycerides / blood


  • Amino Acids
  • Apolipoproteins
  • Triglycerides